C&DH Philip Luers NASA/GSFC Code 561 August 16-17, 2005 NASA’s Goddard Space Flight Center 18b - 1 Requirements Flow-Document Tree LRO Requirements Document 431-RQMT-00011 CRaTER EICD 431-ICD-000094 Diviner EICD 431-ICD-000095 LRO Mission Assurance Requirements RLEP MAR 430-RQMT-000006 MAR LRO ELV Mission Specification RLEP-LRO-P40 MRD LRO ELECTRICAL SPEC 431-SPEC-00008 LRO Mechanical Environments and Verification Requirements 431-RQMT-000012 LAMP EICD 431-ICD-000096 LAMP DICD 431-ICD-000106 LRO Radiation Requirements 431-RQMT-000045 LRO PSE ICD 431-ICD-000018 LEND EICD 4301-ICD-000097 THERMAL SYSTEM SPEC 431-SPEC-000091 LOLA EICD 431-ICD-000098 COMMUNICATION SYSTEM REQUIREMENTS 431-REQT-000137 LROC EICD 431-ICD-000099 LROC DICD 431-ICD-000109 LRO Flight Software Requirements 431-REQT-000139 C&DH Requirements 431-RQMT-000168 SpaceWire SPEC 431-SPEC-000103 CDH FSW 1553B Bus Spec 431-SPEC-000102 LVPC REQs Section 6 SBC REQs Chassis REQs Section 14 HK/IO REQs NASA’s Goddard Space Section 7 Flight Center Section 8 Thermal REQs Section 9 SSR REQs Section 10 KaComm REQs Section 11 S-Band REQs Section 12 Backplane REQs Section 13 18b -2 Lunar Reconnaissance Orbiter (LRO) C&DH System Level 2 Flow Down Key Requirements to all C&DH Sub-Assemblies Level 2 Req. Level 3: Requirements Paragraph Concept/Compliance Requirement MRD-033 1.3.3.3 Electrical Interfaces: C&DH shall comply with the LRO Electrical System SPEC 431-SPEC000008. Each Board has the electrical breakdown documented in Section 3 of its requirements. Power Consumption and Inrush Current are documented. MRD-034 1.3.3.4 Thermal Interfaces: C&DH shall comply with the LRO Thermal System Specifications 431SPEC-000091 Box meets these requirements. Section 5 of each board details additional thermal methods taken (i.e. heat sinks) to meet LRO Thermal requirements. MRD-068 1.4.12 EEE Parts Radiation: C&DH shall meet the requirements of the LRO Radiation Requirements Doc 431-RQMT-00045 Section 1.1 of each board details additional radiation requirements and mitigation where necessary. NASA’s Goddard Space Flight Center 18b - 3 Lunar Reconnaissance Orbiter (LRO) C&DH System Level 2 Flow Down Key Requirements to Single Board Computer (SBC) Level 2 Req. Level 3: Requirements Paragraph Concept/Compliance Requirement MRD-086 3.5.4.1 FSW and ACS SW Processing Storage: The SBC shall provide TBD MIPS processing platform for FSW and ACS SW. This value is based on a 5 second average CPU utilization calculation as required in the GFSC-STD-1000 pg 60 and table 3.07-1. MRD-108 3.5.4.2 Boot Code Storage: The SBC shall provide minimum 64KB of non-reprogrammable (in-flight) non-volatile storage of SUROM boot code. To mitigate the potential EEPROM Radiation and soft-bit issues, PROM is used for SUROM boot code. MRD-108 3.5.4.3 Application Code Storage: The SBC shall provide minimum 4MB of non-reprogrammable (in-flight) non-volatile storage for EEPROM application code. To mitigate the potential EEPROM Rad and soft-bit issues, the 4MB EEPROMs are used to store 2 identical flight application code images with a hardware switchover option. MRD-108 3.5.4.4 Executable Code Storage: The SBC shall provide minimum 20MB of volatile storage for SRAM executable code storage. Storage for applications code, data tables, data. MRD-109 3.5.1.1.2 1553B Bus Controller: The SBC shall operate as Bus Controller (BC) for 1553B as a default. Designed to operate as either BC or RT on 1553B. NASA’s Goddard Space Flight Center 18b - 4 Lunar Reconnaissance Orbiter (LRO) C&DH System Level 2 Flow Down Key Requirements for Data Volume Level 2 Req. Level 3: Requirements Paragraph Concept/Compliance Requirement MRD-118 3.5.4.5 SBC SRAM Data Storage: The SBC shall provide a minimum of 20 MB memory for storage of housekeeping data whenever the SSR is off. Whenever the Solid State Recorder is turned off, all spacecraft and housekeeping data shall be recorded in the SBC. SBC shall have additional SRAM for data storage. MRD-037 3.5.7.1 SSR Data Storage: Normal Operations: The SSR shall provide at least 400Gbits End Of Life (EOL) of memory capacity for incoming data files for science data and housekeeping data collection. SSR Storage requirement: (Based on 4 ground station passes back to back, each 45 minutes long with the time between last and first pass is ~1044 minutes). SSR needs to store 6.4 Mbps (6.4x10e6) average data rate (includes all instruments and S/C engineering) for at least 1044 minutes. Gives approximately 391 Gbits (3.91x10e11) (assuming max LROC data, 16 NAC pairs per orbit). Also based on downlink rate of 125 Mbps (1.25x10e8). NASA’s Goddard Space Flight Center 18b - 5 Lunar Reconnaissance Orbiter (LRO) C&DH System Level 2 Flow Down Key Requirements for Networks Level 2 Req. Level 3: Requirements Paragraph Concept/Compliance Requirement MRD-035 3.5.1.1 Low Speed Bus (LSB) 1553B: C&DH shall utilize a MIL-STD-1553B network per Electrical System Spec 431-SPEC-00008 to interconnect subsystems and instruments for telemetry, commanding, and low speed instrument data. Industry standard interface simplifies interfaces, improves flexibility and supports future growth. MRD-109 3.5.1.1.2 1553B Bus Controller: The SBC shall operate as Bus Controller (BC) as a default. MRD Level 2 requirement. MRD-035 3.5.1.1.3 LSB Scheduling: The C&DH shall initiate predictable transactions on the LSB according to a pre-planned schedule; accurate to +/-5ms and synchronized to the 1 Hz pulse. Ensures reliability of data transfer. MRD-036, MRD-038 3.5.1.2 High Speed Bus (HSB) SpaceWire: C&DH shall utilize a SpaceWire network per LRO SpaceWire SPEC 430-SPEC-000103 to interconnect subsystems and instruments for telemetry, commanding, and high rate data, maximum rate of 125 Mbps (125x10^6). Industry standard interface simplifies interfaces, improves flexibility and supports future growth. Downlink schedule and data volume drive the data rate. NASA’s Goddard Space Flight Center 18b - 6 Lunar Reconnaissance Orbiter (LRO) C&DH System Level 2 Flow Down Key Requirements for Telemetry Level 2 Req. Level 3: Requirements Paragraph Concept/Compliance Requirement MRD-112 3.5.6.1 C&DH Comm Telemetry Encoding: C&DH Comm System shall provide telemetry encoding options i.e. Reed Solomon (RS), Bi-Phase-L, NRZ-L or NRZ-M. All are supported by ground stations. MRD-110 3.5.6.2 C&DH CFDP: C&DH Comm system shall support CFDP. Meets FSW and Comm requirements per LRO 431REQT-000137. MRD-028, MRD-113 3.5.6.3 C&DH Comm Ground Test: C&DH Comm system shall provide a hardline interface for ground test through the spacecraft umbilical. Method for integration and test without using RF components. MRD-110, MRD-123 3.5.6.5.2 S-Band Downlink Telemetry: C&DH S-Band shall support CCSDS downlink telemetry at a maximum rate of 2.186 Mbps (2.186x10^6). Science data and housekeeping data source. Meets Comm requirements per LRO 431REQT-000137 MRD-110, MRD-124 3.5.6.4.1 Ka-Comm Downlink Telemetry: C&DH Ka-Comm shall support CCSDS downlink telemetry at a maximum rate of 125 Mbps (125x10^6). Science data and housekeeping data source including TLM encoding. Meets Comm requirements per LRO 431REQT-000137 NASA’s Goddard Space Flight Center 18b - 7 Lunar Reconnaissance Orbiter (LRO) C&DH System Level 2 Flow Down Key Requirements for Commands Level 2 Req. Level 3: Requirements Paragraph Concept/Compliance Requirement MRD-119, MRD-122 3.5.6.5.1 C&DH S-Band Telecommand: C&DH shall support CCSDS telecommands at a maximum rate of 4 Kbps (4x10^3). Consistent with requirements of flight software and communications. C&DH can support up to 16Kbps (1.6x10e4). MRD-111 3.5.6.5.1.1 C&DH Hardware Decoding: C&DH shall perform hardware decoding of critical commands. Generate 5 RS422 outputs. Method for recovery from anomalous conditions. Ongoing safe-mode and recovery scenario studies. C&DH can support up to 8 outputs. NASA’s Goddard Space Flight Center 18b - 8 Lunar Reconnaissance Orbiter (LRO) C&DH System Level 2 Flow Down Key Requirements for Timing Level 2 Req. Level 3: Requirements Paragraph Concept/Compliance Requirement MRD-042 3.5.2.2, 1.3.4.1.1 Barker Time: C&DH shall record the time of receipt of last ground telecommand. To ensure reliability of communication link to the ground station. MRD-068 3.5.2.1 Watchdogs and External Resets: The C&DH shall provide and control a watch dog timer. To prevent a software continuous loop failure. MRD-042 1.3.4.1.2 Other Errors: The timing error due to other error sources shall be less than 1 ms. [The sources of error (clock, stability, accuracy of distribution, latency of timetick, transmit time)] Must be less than 3 ms knowledge requirement. MRD-043 1.3.4.2.1 Oscillator Drift: The onboard oscillator shall not drift by more than 100 ms in 24 hours over the operational temperature range. Maintains ability to execute stored commands within 100 ms of desired UTC time with an accuracy of 1ms. NASA’s Goddard Space Flight Center 18b - 9 Lunar Reconnaissance Orbiter (LRO) C&DH System Level 2 Flow Down Key Requirements for Timing Level 2 Req. Level 3: Requirements Paragraph Concept/Compliance Requirement MRD-157 1.3.4.2.2 Oscillator Stability: The oscillator stability shall meet the timing requirements in Section 1.2.1.1 in the presence of the measurement errors described in Section 1.2.1.2. Selected an oscillator with a frequency stability of 10 ppb. MRD-043 1.3.4.2.3 Time Correction Accuracy: The C&DH shall provide a mechanism to correct Orbiter time to within 100 ms of UTC time. Ensures maintenance of accuracy. MRD-114 1.3.4.3 MET Counter: The C&DH shall provide a Mission Elapsed Timer (MET) that cannot be adjusted. Standard design reduces the design complexity and meets the requirements. MRD-042 1.3.4.3.1 MET Resolution: The MET counter shall have a resolution of 15 microseconds. For accurate commanding. C&DH shall utilize a 16-bit subsecond counter . MRD-043 1.3.4.3.2 MET Rollover: The MET counter shall be capable of operating for 5 years without rollover. No discontinuities wanted. The use of a 28-bit second counter supports rollover not occurring for 8.5 years. MRD-043 1.3.4.4 Pulse Per Second: The C&DH shall provide a 1 Hz pulse as required by the instruments. For timing and synchronization of commands. NASA’s Goddard Space Flight Center 18b - 10 Lunar Reconnaissance Orbiter (LRO) C&DH System Level 2 Flow Down Key Requirements for Instrument Interfaces Level 2 Req. Level 3: Requirements Paragraph MRD-117 1.3.4.5 , 3.5.1.2 2.3.13 2.3.5 Concept/Compliance Requirement RS422 Serial LSB C&DH shall provide an asynchronous 38400 baud RS422 Serial LSB for telemetry and commanding to the LAMP instrument. All telecommands and time messages shall be transmitted to LAMP via an asynchronous 38400 baud RS422 Serial LSB LAMP/Pluto heritage. Meets LAMP DICD 431-ICD000106. LAMP shall transmit science data using LVDS compliant chips. MRD-116 MRD-117 1.3.4.5, 2.3.1.3 Time Message RS422 Serial LSB: C&DH shall provide the LAMP instrument a time message via RS422 serial LSB. Meets LAMP DICD 431-ICD000106. MRD-035, MRD-116 1.3.4.5, 2.1.2.1, 2.2.2.1, 2.4.2.1, 2.5.2.1 Time message 1553B: Meets Instrument ICD’s. MRD-036, MRD-116 1.3.4.5, 2.6.2.1 SpaceWire Time Code Message: C&DH shall provide the LROC instrument a Time Code Message every 1 Hz via SpaceWire. NASA’s Goddard Space Flight Center C&DH shall provide the following instruments a time message via 1553B: CRaTER, Diviner, LEND, and LOLA. Meets LROC DICD 431-ICD0000109. 18b - 11 LRO C&DH Architecture Block Diagram L E N D SUBSYSTEMS (ACS, PSE, PRO/DEP) NAC1 NAC2 WAC D i v i n e r C R A T E R L O L A MiniRF LROC SpaceWire FPGA 32 Mbps 1553B 5 Heater out Unsw.+28V SpaceWire FPGA 8 to 32Mbps (Max.) Hi-Rate Tlm 125Mbps (Max.) 38.4Kbps Serial IF (UART) 1Mbps S-Xpndr HGA Ka-Xmtr Low-Rate Tlm 2Mbps Max & Command 4Kbps HGA Gimbals 2.186 Mbps Max. (HK Downlink) Sw. +28V (Heater) Sw. +28V (Ka-Comm) 2.186 Mbps Max. (LAMP Tlm) 125 Mbps (Science Downlink) 50 Mbps Max. (Tlm) I/O Sw. +28V (SSR) L A M P Unsw. +28V UnSw. +28V (S-Comm) 1PPS 1553 Summit LVPC ( A) BAE 1553 Summit SpaceWire ASIC Thermal Card RAD750 SBC BAE SpaceWire ASIC SSR SpaceWire FPGA HK/IO SpaceWire FPGA KaComm SpaceWire FPGA SComm (B) +28V Power +/-15V, +5V, +3.3V (A) SpaceWire (HSB) +3.3V (B) Backplane (Power & POR) C&DH NASA’s Goddard Space Flight Center 1553B (LSB) 18b - 12 Lunar Reconnaissance Orbiter (LRO) C&DH System Level 2 Verification • Analysis ▪ FPGA/ASIC (Worst-case Timing Simulation, Test Benches) ▪ Board-level (Test Benches, Throughput Performance, Signal Integrity) • Testing ▪ Component • Radiation (+1.5V Linear Regulator, ACTEL FPGA AX series, Micron SDRAM dies) ▪ Subsystem • Board-level (BB, ETU & FLT) • Box-level (ETU & FLT) ▪ Environments • EMI/EMC, Thermal Vacuum, Vibration (FLT) ▪ System I&T • FLATSAT: Subsystems Electrical Interface Testing (ETU) • Spacecraft (FLT) • Orbiter: EMI/EMC, Thermal Vacuum, Vibration, Acoustic (FLT) NASA’s Goddard Space Flight Center 18b - 13 Lunar Reconnaissance Orbiter (LRO) C&DH System Level 2 Summary • • • • • C&DH Level 2 Requirements are defined, and are traceable to LRO requirements. ▪ C&DH architecture meets these requirements. All C&DH requirements have been captured in a requirements document. ▪ Requirements and technical resources have been allocated to assemblies. C&DH Requirements are in the process of submission to CM for release. Key Interface Requirements are defined. ▪ Have initiated ICD-Level interface definition, some TBD’s pending. Key Trade Studies and Analyses have been completed (Data Volume, 1553B, SpaceWire) C&DH is ready to continue Preliminary Design. NASA’s Goddard Space Flight Center 18b - 14